Snap action switch



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SNAP ACTION SWITCH Filed Dec. l0, 1954 2 Sheets-Sheet 2 :EnEr- .60a ma.

30a. E E fr.- L --J Il I 4. .lll/1111111111111 SNAP Ac'rIoN SWITCHHarold T yzack, Schiller Park, Ill., a'ssignor to Carter Parts Company,Chicago, Ill., a corporation of Illinois Application December 10, 1954,Serial No. 474,343

4 Claims. (Cl. 208-67) The present invention relates to a snap actionswitch, and more particularly to an improved element for effectingmovement of a movable contact by a snap action into and from engagementwith a fixed contact.

It is an object of the present invention to provide a snap switch whichis constructed and arranged so that the contacts are opened or closedwith a snap action 'irrespective of the rate of movement of the forcewhich is applied to the actuating mechanism of the switch.

It is another object of the present invention to provide a snap switchof the foregoing character in which the movable parts of the snap switchcomprise three parts, two of which are spring elements, such parts beingconstructed and arranged so that the opposing forces of the springelements cancel each other in such a manner that a state of staticequilibrium is attained, thereby enabling the three component parts tobe assembled in a subassembly and handled in production as such.

It is another object of the present invention to provide a snap switchof the foregoing character in which a novel arrangement of parts isprovided so that a minimum of i uniform operating characteristics can beobtained from standard parts without requiring adjustment of theaforesaid sub-assembly or the complete assembly, thereby aiding inreducing production costs to a minimum.

It is still another object of the present invention to provide a snapswitch of the foregoing character in which the spring elements in thesub-assembly can be used with equal facility in either a double throwsnap switch or a normally closed or normally open type of snap switch.

Other objects of this invention will appear in the following descriptionand appended claims, reference being had to the accompanying drawingsforming a part of this specification wherein like reference charactersdesignate corresponding parts in the several views.

In the drawings:

Fig. 1 is a plan view of a normallly open or closed snap switchembodying the present invention;

Fig. 2 is a section taken on the line 2-2 of Fig. 1;

Fig. 3 is a section taken on the line 3 3 of Fig. 2;

Fig. 4 is an end elevation of the embodiment shown in Figs. 1 to 3;

Fig. 5 is a section similar to Fig. 2 of a double throw snap actionswitch embodying the present invention;

Fig. 6 is a section taken on the line 6-6 of Fig. 5; and

Fig. 7 is an end elevation of the embodiment shown in Figs. 5 and 6.

Before explaining the present invention in detail, it is to beunderstood that the invention is not limited in its application to thedetails of construction and arrangement of parts illustrated in theaccompanying drawings, since the invention is capable of otherembodiments and of being practiced or carried out in various ways. Also,

United States Patentice tion of the present invention will be given. Theembodiment shown in Figures l to 4 includes a housing 10 of insulatingmaterial having a front section 12 and a rear section 14 which aresecured together by a pair of rivets 16. Pins 18 are an integral part ofthe section 14 and fit into mating holes in section 12 to aid inassembling the casing sections. Holes 20 may also be provided for use inmounting the switch unit.

The housing 10 has a cavity 22 within which is carried a sub-assembly ofthree parts, the contact carrier 24, the actuator 26 and the U-shapedrocker spring 28. Riveted to the stationary end of the contact carrier24 is a terminal 30. These parts can be joined together as vasub-assembly, if desired, and can be inserted directly into the housing10 as a single unit.

The contact carrier 24 is mounted in the housing 10 in cantileverfashion so that the end to which terminal 30 is attached will be rigidlyheld, and the opposite end will be free to move between the stationarycontacts32 and 34. The latter are directly connected with the terminals36 and 38. The movable end of contact carrier 24 has the contacts 40 and42 securely mounted thereon, and they are adapted to engage thestationary contacts 32 and 34.

The contact carrier 24 is formed by a stamping operation from anysuitable conducting metal and has a U- shaped cut-out 44 by which aspring arm 46 is formed Within the contactor arm 48. The free end ofspring arm 46 has a V-shaped notch cut therein and the notch comes to aknife edge as can be seen in Figure 2. The V-shaped notch straddles theactuator 26 in the circular groove 50 which circumscribes the actuator,the knife edge of spring arm 46 being the only portion of the latter tobe in engagement with the actuator 26.

The U-shaped rocker spring 28 has a V-shaped notc cut in one of itsends, and this notch also comes to a knife edge. This notch straddlesthe actuator 26 in the circular groove 50 but in a positiondiametrically opposite the spring arm 46, and, as in the case of springarm 46, only the knife edge engages the actuator 26. The opposite end ofthe U-shaped rocker spring 28 'has a slot 52 which receives a tongue S4extending from the contactor arm 48. The edge 56 of contactor arm 48comes to a knife edge so that when the rocker spring 28 tilts or pivots,in a manner to be described, the bearing surface between the rockerspring 28 and the contactor arm 48 is limited primarily to the knifeedge 56. lThus, it can be seen that substantially the only points ofengagement between the three movable parts, the contact carrier 24, theactuator 26 and the rocker spring 28 are knife edges and those` in thegroove 50 are essentially point contacts so that the tilting or pivotingaction that occurs between these parts is practically frictionless.

in the normal operation of this embodiment of the invention, the coilspring 58 will urge the actuator 26 to its uppermost position in thehousing 10 with the push button end portion of the former projectingthrough the opening 6). The movable contact 42 Will be in engagementwith contact 34 so that the terminals 30 and 38 may be connected ineither a normally open or normally closed circuit, as desired.

The contact 42 can be moved away from stationary contact 34 and contact48 moved into contact with stationary contact 32 by a snap action merelyby pressing down on the button end of actuator 26. With the switch inthe position shown in Figure 2 the rocker spring 28 is in a state ofcompression so that the ends are exerting `anequal but opposite thrustagainst the actuator 26 and the contacter arm 48. Since the ends of therocker spring 28 are in a plane that is inclined to the plane of thecontacter arm 48, the spring 28 will exert a compejiient of pressuretending to hold the contact 42 against stationary contact 34. However,whenilthe plane eentaining uend s of` the rocker spring 28`pass'es intoarid thereafter tilts beyond the plane Aof'contacterar'ni 4 8,

tion shown in Figure 2 arid as the ends Vof 'the rocker spring 28 passthrough the plane` of the oontact'or 48 the forces exerted by` -therocker' spring 28 will he such as Vto cause the sub-assembly 'to returnto the position shown in Figure`2. In order to aid in maintaining unifoiopration of the svv'itcli and to assure that the Snap Vctiil Will Ccl'irt S''bst'tilly flic Same posinon of 'navi-.nient of die 'actuator 26,the edges or the contacter rf 48 are folded over as at 60, therebypreventing bowing of the contactenY a'r'rn' '48 and assuring thatfit'will remain in suosta'ntially 'one' 'plane' during opti f the Switch.

Front the foregoing it can be seen that the movements of the componentparts' are substantially frictionles's and the parts' are supported sothat there can be ne misalignment or' shifting which may cause irregularoperation. Since thepa'rt's will encounter substantially no wear nor' isthere" any likelihood of damage, a very long life is assured.

The present invention is not limited in use to a precise switch of thetype described above. Other applications of the invention can be made,and one such application is' illustrated in Figures 5 to 7. Thismodification is the same as the one previously described, but it is adouble throw switch which has an actuator 26a which projects' throughthe openings 4`6021 in both the' top and bottom of the housing a. Thus,the contacts 40 and 42 will remain in engagement with whichever ofstationary contacts 32a or 34a as may be selected, merely 'by' pressingthe actuator y26a to its upper position shown,

or Ato' a corresponding lower position which will cause Contact 40ct tobe in engagement `with stationary contact 32a. In other respects thismodification isl the same as the one illustrated in Figures 1 tol 4' andreference is made to the description of that niediiication for anyy ofthe other parts ct the present modification.

Having thus described my invention, I claim:

1. In a snap action switch, a contacterv element comprising a springblade'having a U-shaped cut-out s'o as to form a hat spring arm within acontacter arm,` the Vfree end of said spring armhaving a V-shaped knifeedge,

a rocker spring pivotally connected to said contacter arm and having anend with a V-'shaped knife edge disposed opposite to the correspondingedge' of the spring arm, and an actuatorv extending axially through thecut-out' of the spring blade', said actuator having a circumferentialgroove for receiving said knife edges so that each of the latterstraddles said actuator making peint contacts therewith and the springarm and rocker spring are movable on axial movement of said actuator,said actuator also having a spring for urging the spring arm and rockerspring in one direction and a push button for manually moving theseelements in the opposite direction.

2. In a snap action switch, a contacter element cornprising a springblade having a U-shaped cut-out so as to term a hat spring arm within acontacter arm, the free end of said spring arm having a V-'shaped knifeedge, a rocker spring pivotally connected to said contacter arm andhaving an end with a V-'shaped knife edge disposed opposite to thecorresponding edge of the spring arm, and an actuator extending axiallythrough the cut-out of the spring blade, said actuator having acircumferential groove for receiving said knife edges so that each ofthe latter straddles said actuator making point contacts therewith andvthe spring arrn and rocker-spring are inevahle on laxial movement ofsaid actuator, lsaid actuator also having push buttons on its oppositeends for selectively movig the spring arm iii opposite directions.

3. Ina 'snap action sivith, the combination comprising a fixed Contact,a 'contacter element including a spring blade with a U-shap'ed cut-'outso as to forth a spring ari within a contacter arr'n, the free Yend ofsaid spring arr'n having a V-shp'ed knife edge, a rocher springpivotally connected to' 'saidvconta'citor arni and having an end with atl-shaped knife edge disposed opposite to the corresponding edge of thcspring arm, and an actuator red extending axially through the cut-out ofthe 'spi-ing blade, said actuator rod having a circumferential groovefor receiving said knife edges so that each of the latter straddles saidactuator rod making point contacts therewith, said spring blade carryinga `contact movable inte contact with said xed Contact so that movementof said actuator rod will effect rhovcr'nent of the movable contactby asnap action into and 'from engagement with the fixed Contact.

4. In a snap action switch, the combination defined in claim 3'wher'einthe lateral edges of said contacter arm opposite the c ut out of theblade are bent over te prevent bowing of this portion of the contacterarm.

References Cited in the file of this patent UNirED STATES PATENTS2,429,812 Hausler Oct. 28, 1947 2,459,661 MacFarla-nd Jan. 18, 19492,538,512 Gates et al.- Jan. 16, 1951 2,556,216 Raney -e June l2, 19512,594,216 Reeser a Apr. 22,I 1952 2,598,856 Swan et al. -e `June 3, 19522,599,473` Miller Y -2 2 June 3, 1952 2,626,999 Johnson f -a lan. 27',1953 2,629,791 Tourneau l v Feb. 24,- 1953 2,644,052 Martin n- June 30,1,953 2,748,214 Irnrnel May 29, 1956

